FYI - The above message is not very intuitive, in my instance it should have read "User Account Does Not Have An Appropriate License Assigned to Them In Microsoft 365".  It seems that my test user account had it's Microsoft 365 Business Standard license remove.

Would you want the documentation - perhaps troubleshooting updated - or the message changed?

My assumption is that this error is not being generated by Sage CRM itself, it is being generated by Exchange 365 and then passed through the Sage CRM UI.  Ideally it would be great to get a "User Account Does Not Have An Appropriate License Assigned to Them In Microsoft 365" message in the UI, but can this error be triggered in other situations?  Sometimes a piece of software can give a misleading error message which points people in the wrong direction.  This is worse as you try to fix the wrong issue.

Updating the documentation would be a good start, stating something like

If you receive the error message "Parsing OData Select and Expand failed: Could not find a property named 'sender' on type 'microsoft.graph.mailFolder'" first confirm that the 365 user you attempting to file emails for has the correct licenses assigned to it within 365.

Hopefully by adding this a a post here if anyone searches for this error message they will see this post and have a potencial resolution anyway.